During the third year of this investigation we shall evaluate exercise-induced changes in arterial hemoglobin saturation by oximetry and the development of lactic acidosis during and after exercise in normal and asthmatic children. We shall assess the relation of any changes in these parameters to exercise-induced alterations in lung functions. Considerable time and effort will be devoted to analysis of data collected during the past 2 years, and to the preparation of manuscripts. Bibliographic references: Cropp, G.J.A.: Exercise-induced asthma. Ped. Clin. N. Amer. 22: 63-76, 1975; Cropp, G.J.A.: Effectiveness of atropine sulfate as a bronchodilator in asthmatic children. Am. Acad. Allergy, February, 1975.